Naturally occurring signals such as image, radio waves, light, and sound signals are analog. These signals can be amplified/filtered in the analog domain and converted to digital signals for further processing. Devices used to sense and detect analog signals and/or process and analyze analog signals have limited accuracy and linearity. Such devices can detect and amplify not only the desired signals but also generate other spurious signals. For instance, an amplifier(s) or amplifiers with an active filter may be operated in regions where harmonic distortions become significant and limit the accuracy of a detection level of a desired signal. An analog to digital converter (ADC), which converts analog signals to the digital domain, may contain a highly nonlinear circuit such as a sample and hold and a comparator that introduces non-linear errors, and/or be preceded with a nonlinear analog front-end (e.g. pre-amplifier, input network, etc). For example, an error in any or all of sampling and gain and offset in the ADC during sampling of a finite analog level can result in a large number of harmonic distortions. FIG. 1 is a graph of an example of an ADC output signal, which is plotted in frequency domain. A single frequency tone is filtered and applied as an input to the ADC. As illustrated, the Fast Fourier Transform (FFT) output spectrum of the signal from the ADC has many orders of harmonic distortions. Even 100th order harmonics can be visible depending on the noise floor of the signal spectrum. FIG. 2 illustrates an example of the FFT output spectrum of the signal from the ADC with two input frequency tones applied at the input to the ADC. The figure illustrates that the ADC output signal has many intermodulation distortions. Thus, if a signal is broadband, occupying more than a single frequency tone, and the broadband signal enters a nonlinear circuit such as any of the devices mentioned above, the desired output signal will contain spurious harmonic and intermodulation distortion content. For systems requiring high fidelity in sound, clear image, uncorrupted RF and optical signals, it is important to recover or maintain the spectral purity of the input signal in the frequency domain and/or minimize distortion in time domain. Nonlinear systems can be used to detect small signals in the presence of signals with significantly larger amplitudes. Such detection typically requires a high spur-free dynamic range (SFDR), which is a measure of the amplitude of the fundamental with respect to the amplitude of the largest harmonic tone or spur.